Why I lost all configuration when I Upgrade firmware for T40
No idea. I had no problem upgrading my T20, which runs the same as a T40.
What were you using to do the upgrade? The Web UI or ???
I used WSM Policy Manager.
From what version did you upgrade & to what version ?
I do an upgrade for every new version and for most betas - my last upgrade was to 12.7.2. I have never experienced this for any upgrade on any of my firewalls. This can happen on a downgrade.
Did you save a config prior to your upgrade?
I use it the cloud but of courrse I have the config file locally.
Since you used the cloud, and the cloud processes are fairly new - you should open a support incident on this so that WG can investigate this.
I always use system manager to get a copy of running config before doing any upgrades.